Load balancer

Description and cases

The SSG can act as a traffic balancer based on IP addresses belonging to an AS defined as local in asnum.dscp.
In this case, the SSG-LB acts as an L2-bridge in the network, hence the name L2 traffic balancer.

DPI functionality does not work in this mode.

Case: Balancer on a traffic mirror

Suppose a 400Gbps traffic mirror needs to be evenly distributed among four VAS platforms (Value-Added Services) performing traffic analysis and various detection.
In this case, SSG-LB will evenly distribute traffic with equal port utilization on the pullers and maintain traffic symmetry (traffic from one session will be directed to only one puller).

Example configuration /etc/dpi/fastdpi.conf:

Traffic mirroring is fed into 4x100G interfaces.

Traffic is balanced between four pullers, each puller is connected by 4x25G links.

in_dev=05-00.0:05-00.1:05-00.2:05-00.3 out_dev=01-00.0:01-00.1:01-00.2:01-00.3:02-00.0:02-00.1:02-00.2:02-00.3:03-00.0:03-00.1:03-00.2:03-00.3:04-00.0:04-00.1:04-00.2:04-00.3 #FastDPI Control ctrl_port=29000 ctrl_dev=lo #Turn on Load Balancing enable_l2_lb=1 #Balance algorithm maglev=2 #Hash table lb_hash_out_dev_type=1

Setting

Setting up subnets for balancing

Balancing applies only to IP addresses belonging to the AS defined as local in asnum.dscp.

Define an autonomous system with IP addresses that are used by subscribers:

vi aslocal.txt 10.0.0.0/8 64511 172.16.0.0/12 64511 192.168.0.0/16 64511 cat aslocal.txt | as2bin /etc/dpi/aslocal.bin

Examples for IPv4

Example for IPv6

Mark a given autonomous system as local:

vi my_as_dscp.txt 64511 local 10415 local cat my_as_dscp.txt | as2dscp /etc/dpi/asnum.dscp

You can use either a custom AS or a public AS as the AS.
Read more at the link

A reload must be performed to apply the parameters:

service fastdpi reload

Setting /etc/dpi/fastdpi.conf

Define the input and output interfaces in the configuration file.
The input interfaces to which the traffic mirror is fed are specified in the in_dev parameter, and the output interfaces are specified in out_dev.
Interfaces do not form pairs and species constructs are allowed:

in_dev=05-00.0:05-00.1:05-00.2:05-00.3:0b-00.0:0b-00.1:0b-00.2:0b-00.3 out_dev=08-00.0:08-00.1:08-00.2:08-00.3

Or

in_dev=05-00.0 out_dev=out_dev=08-00.0:08-00.1:08-00.2:08-00.3

Enable balancing mode in the enable_l2_lb parameter, where:

0 — deactivate balancing;

1 — activate balancing.

Determine by what value to initialize the hash table in the lb_hash_out_dev_type parameter, where:

0 — use the internal index of the output interface;

1 — use the interface name from [in|out]_dev.

Select an engine to handle thread dispatchers in the dpdk_engine parameter, where:

0 — read/write default engine, one dispatcher for everything;

1 — read/write engine with two dispatcher threads: a dispatcher for each direction;

2 — Read/write engine with RSS support: for each direction, dpdk_rss dispatchers are created (default dpdk_rss=2), so total number of dispatchers = 2 * dpdk_rss.
Learn more about the dpdk_engine parameter by clicking here.

Select a balancing algorithm. The maglev algorithm with fixed hash table size is used for traffic balancing, where:

1 — if src and dst ip are both local, then hash is calculated based on these two addresses;

2 — if only src ip local, then hash is calculated based on src ip;

3 — if only dst ip local, hash is calculated on the basis of dst ip;

4 — hash is calculated based on src and dst ip.
Based on the calculated hash value, the output interface is determined by determining the index of the hash table cell containing the interface index from the array of output interfaces.

SSG-LB equipment requirements

Max IN traffic Gbps (Mirror on SSG-LB)	Max OUT traffic Gbps (Balanced traffic to the removers)	SSG-LB version	Number of cores per one CPU with frequency of 2.5 GHz or more	RAM GB	Type and minimum number of ports	Packet per second in millions at a base CPU frequency of 2.5GHz or more
up to 100	up to 100	SSG-100-LB	28 Intel 6258R, Intel 5320, 32 AMD 7502P	64 (8x8GB)	2x100G + 14x10/25G	40M pps
up to 200	up to 200	SSG-200-LB	64 AMD 9534	64 (8x8GB)	9x25/40/50/100G	60M pps
up to 300	up to 300	SSG-300-LB	96 AMD 9654	64 (8x8GB)	9x25/40/50/100G	80M pps
up to 400	up to 400	SSG-400-LB	128 AMD 9754	64 (8x8GB)	9x25/40/50/100G	120M pps